Injection mold temperature control method for automobile part production

Abstract

The invention relates to the technical field of temperature control, in particular to an injection mold temperature control method for automobile part production, which comprises the following steps of: respectively finishing the first temperature regulation of a cavity and a core according to the difference between the temperature values of the cavity and the core at the current moment and a required temperature value, and after the first temperature regulation of the cavity and the core, controlling the temperature of the cavity and the core to be lower than the required temperature value; and the temperature value of each monitoring point in the cavity and the mold core at the next moment of the current moment and the flow speed of cooling liquid in the cavity and the mold core cooling system are obtained, so that the local temperature difference consistency of the temperature areas of the cavity and the mold core is determined, and secondary temperature adjustment of the cavity and the mold core is completed. The temperature control precision of the injection mold can be improved, and high-precision production of high-precision automobile parts is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature control, and in particular to a temperature control method for an injection mold used in the production of automobile parts. Background Art

[0002] Injection mold temperature control plays a vital role in the production of automotive parts. With the continuous development of the automotive manufacturing industry, the requirements for parts are becoming increasingly stringent, especially in terms of precision, strength, and appearance quality. As a common production method, injection molding boasts advantages such as high efficiency, low cost, and the ability to manufacture complex shapes. However, controlling the injection mold temperature directly impacts the quality of the final product and production efficiency, which is particularly important in the production of high-precision, high-performance automotive parts. Therefore, researching and developing more efficient and intelligent mold temperature control methods is crucial for the future production of automotive parts.

[0003] Existing problems: Traditional mold temperature control is usually achieved by cooling and heating the entire mold as a whole. The cooling involved is simply to adjust the mold cooling by controlling the temperature of the coolant. However, the production of automotive parts has high precision requirements. For example, complex deep-cavity parts have different cooling rates at different positions, so one temperature zone cannot meet the actual needs. At the same time, during the cooling process of the sub-temperature zones, local temperature differences often exist, and different control strategies are required when the sources of local temperature differences are different. Conventional zone temperature control methods are less effective in solving local temperature differences. Summary of the Invention

[0004] The present invention provides a temperature control method for an injection mold used in the production of automobile parts, so as to solve the existing problems.

[0005] The present invention provides a method for controlling the temperature of an injection mold for the production of automotive parts using the following technical solutions: One embodiment of the present invention provides a method for controlling the temperature of an injection mold for the production of automotive parts, the method comprising the following steps: Obtain the current temperature values ​​of the cavity and core and the required temperature values; determine the probability of water temperature adjustment of the cavity and core based on the difference between the current temperature values ​​of the cavity and core and the required temperature values; and perform the first temperature adjustment of the cavity and core based on the probability of water temperature adjustment of the cavity and core; After the first temperature adjustment of the cavity and the core, the temperature value of each monitoring point in the cavity and the core at the next moment after the current moment, as well as the coolant flow rate in the cooling system of the cavity and the core, are obtained; based on the distance between the monitoring points and the temperature value difference between the cavity and the core at the next moment after the current moment, the consistency of the local temperature difference in the temperature zone of the cavity and the core is determined; According to the consistency of the local temperature difference in the temperature zones of the cavity and the core, combined with the temperature value difference between the monitoring points in the cavity and the core at the next moment and the coolant flow rate in the cooling system of the cavity and the core, the second temperature adjustment of the cavity and the core is completed respectively.

[0006] Furthermore, the determination of the probability of adjusting the water temperature of the cavity and the core includes the following specific steps: At the current moment, obtain the absolute value of the difference between the required temperature values ​​of the cavity and the core, and record it as the theoretical temperature difference value between the cavity and the core; obtain the absolute value of the difference between the temperature values ​​of the cavity and the core, and record it as the actual temperature difference between the cavity and the core; determine the required temperature adjustment rate according to the actual temperature difference between the cavity and the core and the theoretical temperature difference between the cavity and the core; obtain the absolute value of the difference between the required temperature value of the cavity and the temperature value, and record it as the cavity temperature deviation value; obtain the absolute value of the difference between the required temperature value of the core and the temperature value, and record it as the core temperature deviation value; determine the probability of water temperature adjustment of the cavity and the core according to the required temperature adjustment rate, the cavity temperature deviation value and the core temperature deviation value.

[0007] Furthermore, the specific steps of determining the temperature adjustment rate requirement value include the following: A normalized value of the absolute value of the difference between the actual temperature difference between the cavity and the core and the theoretical temperature difference between the cavity and the core is obtained, and recorded as the temperature adjustment rate requirement value.

[0008] Furthermore, the method of determining the probability of water temperature adjustment of the cavity and the core respectively according to the temperature adjustment rate requirement value, the cavity temperature deviation value, and the core temperature deviation value includes the following specific steps: Obtain the normalized value of the product of the inverse proportional value of the temperature regulation rate requirement value and the cavity temperature deviation value, and record it as the cavity water temperature regulation probability; obtain the normalized value of the product of the inverse proportional value of the temperature regulation rate requirement value and the core temperature deviation value, and record it as the core water temperature regulation probability.

[0009] Furthermore, the first temperature adjustment of the cavity and the core is completed respectively according to the probability of the water temperature adjustment of the cavity and the core, and the specific steps include the following: At the current moment, if the cavity water temperature adjustment probability is greater than the preset adjustment threshold, the fuzzy control algorithm is used to adjust the coolant temperature in the cavity cooling system. If the cavity water temperature adjustment probability is less than or equal to the preset adjustment threshold, the fuzzy control algorithm is used to adjust the coolant flow rate in the cavity cooling system to complete the first temperature adjustment of the cavity. According to the method of completing the first temperature adjustment of the cavity, the first temperature adjustment of the core is completed according to the probability of the core water temperature adjustment.

[0010] Further, the specific steps of determining the temperature zone local temperature difference consistency of the cavity and the core include the following: In the next moment of the current moment, an average value of temperature values of all monitoring points in the cavity is obtained, denoted as a first average value, a normalized value of an absolute value of a difference between a temperature value of each monitoring point in the cavity and the first average value is obtained, denoted as a temperature value anomaly probability of each monitoring point, and monitoring points with a temperature value anomaly probability greater than a preset temperature anomaly threshold are all denoted as abnormal monitoring points. According to a distribution of the abnormal monitoring points in the cavity in the next moment of the current moment, local temperature difference monitoring points in the cavity in the next moment of the current moment are screened from the abnormal monitoring points. According to an acquisition mode of the local temperature difference monitoring points in the cavity in the next moment of the current moment, local temperature difference monitoring points in the core in the next moment of the current moment are obtained. According to a difference between distances of the local temperature difference monitoring points between the cavity and the core and temperature value anomaly probabilities, the temperature zone local temperature difference consistency of the cavity and the core is determined.

[0011] Further, the specific steps of screening the local temperature difference monitoring points in the cavity in the next moment of the current moment from the abnormal monitoring points include the following: A preset quantity threshold N is set, in the next moment of the current moment, a shortest path length between any two abnormal monitoring points in the cavity is obtained by using a Dijkstra algorithm, a sum value of the shortest path lengths between each abnormal monitoring point and all other abnormal monitoring points in the cavity is obtained, denoted as a dispersion of each abnormal monitoring point, and the first N abnormal monitoring points with the smallest dispersion are all denoted as the local temperature difference monitoring points in the cavity in the next moment of the current moment.

[0012] Further, the specific steps of determining the temperature zone local temperature difference consistency of the cavity and the core according to the difference between the distances of the local temperature difference monitoring points between the cavity and the core and the temperature value anomaly probabilities include the following: In the next moment of the current moment, from all the local temperature difference monitoring points in the cavity, a local temperature difference monitoring point in the cavity closest to each local temperature difference monitoring point in the core is obtained, denoted as a matching cavity monitoring point, a reciprocal normalized value of a distance between each local temperature difference monitoring point in the core and the matching cavity monitoring point is obtained, denoted as a position consistency, a reciprocal normalized value of an absolute value of a difference between a temperature value anomaly probability of each local temperature difference monitoring point in the core and the matching cavity monitoring point is obtained, denoted as a temperature difference consistency, an average value of the position consistency and the temperature difference consistency is obtained, denoted as a local temperature difference consistency relationship of each local temperature difference monitoring point in the core, and an average value of the local temperature difference consistency relationships of all the local temperature difference monitoring points in the core is obtained, denoted as the temperature zone local temperature difference consistency of the cavity and the core.

[0013] Furthermore, the second temperature adjustment of the cavity and the core is completed based on the consistency of the local temperature difference between the temperature zones of the cavity and the core, combined with the temperature difference between the monitoring points in the cavity and the core at the next moment and the coolant flow rate in the cooling system of the cavity and the core, and the specific steps include the following: At the next moment after the current moment, for all monitoring points in the cavity, the monitoring points whose temperature abnormality probability is less than or equal to the preset temperature abnormality threshold are recorded as normal monitoring points in the cavity at the next moment after the current moment; When the consistency of the local temperature difference between the temperature zones of the cavity and the core is greater than the preset classification threshold, the mean of the temperature values ​​of all abnormal monitoring points in the cavity is obtained and recorded as the second mean, and the mean of the temperature values ​​of all normal monitoring points in the cavity is obtained and recorded as the third mean. The absolute value of the difference between the second mean and the third mean is recorded as the size of the local temperature difference in the cavity; The second temperature adjustment of the cavity is completed according to the local temperature difference of the cavity and the coolant flow rate in the cavity cooling system; The second temperature adjustment of the core is completed in the same manner as the second temperature adjustment of the cavity.

[0014] Furthermore, the second temperature adjustment of the cavity is completed according to the size of the local temperature difference of the cavity and the flow rate of the coolant in the cavity cooling system, and the specific steps include the following: Based on the principle of fuzzy control, the initial adjustment amount of water flow rate is determined according to the local temperature difference of the cavity; Gets the difference between the preset restricted flow rate and the coolant flow rate in the cavity cooling system , when the difference When it is greater than 0, the difference The inverse proportional normalized value is recorded as the degree to which the current water flow rate is close to the restricted flow rate. When the difference When it is less than or equal to 0, the preset constant is recorded as the degree to which the current water flow rate is close to the restricted flow rate; Obtain the product of the degree to which the current water flow rate approaches the restricted flow rate and the initial water flow rate adjustment amount, and record it as the correction amount of the water flow rate adjustment amount; The sum of the correction amount of the water flow rate adjustment amount and the initial water flow rate adjustment amount is recorded as the final water flow rate adjustment amount; According to the final water flow rate adjustment amount, the coolant flow rate in the cavity cooling system at the next moment after the current moment is regulated to complete the second temperature adjustment of the cavity.

[0015] The beneficial effects of the technical solution of the present invention are: In the embodiment of the present application, according to the difference between the temperature value of the cavity and the core at the current time and the required temperature value, the first temperature adjustment of the cavity and the core is respectively completed, thereby in the temperature control of the injection mold for the production of automobile parts, first, in order to meet the accurate temperature control of complex deep cavity parts, the cavity and the core are independently controlled in different temperature zones, and the temperature control accuracy is improved. After the first temperature adjustment of the cavity and the core, the temperature value of each monitoring point in the cavity and the core at the next time of the current time, and the flow rate of the cooling liquid in the cooling system of the cavity and the core are obtained, so as to determine the local temperature difference consistency of the temperature zone of the cavity and the core, and the second temperature adjustment of the cavity and the core is respectively completed, thereby in the temperature zone control, the local temperature difference is identified, and the consistent relationship between the position performance and the specific temperature difference performance of the cavity and the core when the local temperature difference occurs is utilized to identify the type of the local temperature difference, so as to effectively improve the accuracy of the obtained temperature difference type, and the temperature of different types of local temperature difference is regulated respectively, so as to further improve the accuracy of the mold temperature control. Thus, the present application can improve the accuracy of the temperature control of the injection mold, and is beneficial to the high-precision production of high-precision automobile parts. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1 The step flow chart of the injection mold temperature control method for the production of automobile parts according to the present application is shown in the figure. Figure 2 The injection mold for the production of automobile parts is shown in the figure. DETAILED DESCRIPTION

[0018] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the specific embodiments, structure, features and effects of the injection mold temperature control method for the production of automobile parts according to the present application are described in detail below. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0020] The following describes in detail a specific solution of a temperature control method for an injection mold for automobile parts production provided by the present invention with reference to the accompanying drawings.

[0021] See also Figure 1 , which shows a flow chart of a method for controlling the temperature of an injection mold for producing automotive parts according to an embodiment of the present invention, the method comprising the following steps: Step S001: Obtain the temperature value and required temperature value of the cavity and core at the current moment; determine the probability of water temperature adjustment of the cavity and core based on the difference between the temperature value and required temperature value of the cavity and core at the current moment; and complete the first temperature adjustment of the cavity and core respectively according to the size of the probability of water temperature adjustment of the cavity and core.

[0022] In this embodiment, data collection is performed first. In temperature control of automotive parts injection molds, temperature data collection is the front-end sensing core of closed-loop temperature control. Accurate sensor selection, scientific installation, and efficient data collection are essential to ensure the authenticity, real-time, and uniformity of core and cavity temperature data, providing a reliable basis for subsequent zone adjustment and dynamic phased control. Specifically: (1) Core sensor: The mold temperature is mainly collected by contact sensors, which are directly attached to the mold and have accurate data. In this embodiment, a K-type thermocouple is used, whose temperature range is 0 to 300 degrees Celsius, covering the mold temperature range of commonly used automotive injection molding materials, avoiding data overflow due to insufficient range, and the accuracy level is Class 1, in line with the IEC 60584 standard, meeting the size of automotive parts, and the response time is less than or equal to 1 second, quickly capturing temperature fluctuations to avoid defects caused by lags. The probe structure is a metal sheath type, and the material is 316 stainless steel, which is resistant to oil and coolant corrosion, and anti-vibration. The protection level of the probe part is IP67, which prevents water leakage in the cooling water channel and oil from penetrating into the sensor, causing short circuits or reduced accuracy. The sampling frequency is once per second, which meets the rapid fluctuations of the mold temperature. (2) Sensor installation method: First, drill a hole, that is, drill a blind hole on the side wall or bottom of the cavity (not the surface of the part). The hole diameter is 0.1 to 0.2 mm larger than the diameter of the sensor probe. The hole depth must ensure that the probe tip is 1 to 2 mm away from the cavity surface. Then, drill an axial blind hole according to the core structure. The hole depth is 5 to 10 mm shallower than the core depth and the hole diameter is 0.1 mm larger than the probe. Record the coordinates of all drilling positions, that is, the coordinates of the monitoring point position. Then fix it, that is, insert the sensor probe into the blind hole, fill the gap with high-temperature thermal conductive glue, and ensure that the probe is in close contact with the hole wall. Finally, route the wire, that is, the sensor wire is led out from the wiring groove on the side of the mold. It needs to be reserved when designing the mold. The groove width is 3 to 5 mm. The wire is covered with a metal bellows and finally connected to the data acquisition module. (3) Data acquisition method: The sensor collects real-time temperature data and uploads it to the data processing center. The data processing center is then connected to the injection molding machine temperature control platform and can directly read the cooling system parameters in the injection molding machine temperature control system, including the temperature and flow rate of the coolant. It should be noted that the cavity and core in the mold are two independent temperature zones, and the cooling systems of the two temperature zones are independent of each other. This completes the collection of raw data and uploads the collected data to the data processing center for subsequent data analysis and mold temperature control.

[0023] Preferably, in one embodiment of the present invention, the method for completing the first temperature adjustment of the cavity and the core separately includes: In this way, the temperature value of each monitoring point in the cavity at each moment and the temperature value of each monitoring point in the core at each moment can be obtained, wherein there are multiple monitoring points (hole positions) in the cavity and multiple monitoring points (hole positions) in the core.

[0024] The average temperature value of all monitoring points in the cavity at each moment is taken as the temperature value of the cavity at each moment.

[0025] The average of the temperature values ​​of all monitoring points in the core at each moment is taken as the temperature value of the core at each moment.

[0026] It should be noted that water temperature regulation is further implemented based on the overall internal and external temperature differential. Due to the varying heat distribution and functions of different mold zones, and the high process requirements of automotive parts, different temperature control methods are required. For example, deep-cavity automotive parts require molds consisting of a cavity and a core. Cooling is essentially a process where heat is transferred from the interior of the plastic part to the mold (core and cavity), and then removed through the mold temperature control system. In zoned core and cavity temperature control, the temperature relationship between the two directly mirrors the cooling process of the injection molded part: the core temperature corresponds to the cooling state of the part's inner surface, while the cavity temperature corresponds to the cooling state of the part's outer surface. The temperature differential and synchronization between the two directly determine the solidification rate, thermal stress distribution, and final mold quality of the part's inner and outer layers. Therefore, during the cooling process of an injection molded part, the core and cavity temperature zones each have their own temperature requirements, requiring temperature regulation based on the actual temperature requirements of these zones. The temperature regulation of the cavity and core is mainly to make the actual temperature of the cavity and core meet the temperature requirements. Generally, the cavity and core have different theoretical temperature difference values ​​at different cooling stages, that is, the theoretical temperature difference value between the cavity and core. At this time, if the actual temperature difference between the cavity and core is greater than the theoretical temperature difference value, the temperature balance will be destroyed, that is, a faster regulation rate is required. Schematic diagram of injection molds used in the production of automotive parts, such as Figure 2 shown.

[0027] Get the required temperature value of the cavity and the required temperature value of the core at each moment.

[0028] The absolute value of the difference between the required temperature value of the cavity and the required temperature value of the core at each moment is recorded as the theoretical value of the temperature difference between the cavity and the core at each moment.

[0029] It should be noted that the material supplier data can be used to obtain the temperature values ​​required for the cavity and core at each stage of the mold injection process (such as the plastic melting stage, injection stage, and pressure holding stage). Based on the stage at each moment, the required temperature values ​​of the cavity and core can be obtained.

[0030] At the current moment, the absolute value of the difference between the temperature value of the cavity and the temperature value of the core is obtained, and recorded as the actual temperature difference between the cavity and the core.

[0031] At the current moment, obtain the absolute value of the difference between the actual temperature difference between the cavity and the core and the theoretical temperature difference between the cavity and the core The normalized value of is recorded as the temperature regulation rate requirement value.

[0032] It should be noted that: in this embodiment, As The normalized value of is a linear normalization function used to normalize data values ​​to between 0 and 1. It is known that temperature regulation during the cooling process of injection molded parts mainly involves regulating the water temperature and water flow rate of the water cooling system. Water temperature regulation has a wider adjustment range, while flow rate regulation has a faster rate.

[0033] At the current moment, the absolute value of the difference between the required temperature value of the cavity and the temperature value of the cavity is obtained, which is recorded as the cavity temperature deviation value; the absolute value of the difference between the required temperature value of the core and the temperature value of the core is obtained, which is recorded as the core temperature deviation value.

[0034] At the current moment, obtain the product of the inverse proportional value of the temperature regulation rate requirement value (i.e. 1 minus the difference between the temperature regulation rate requirement value and the cavity temperature deviation value) The normalized value of is recorded as the cavity water temperature adjustment probability, and the product of the inverse proportional value of the temperature adjustment rate demand value and the core temperature deviation value is obtained. The normalized value of is recorded as the core water temperature adjustment probability.

[0035] It should be noted that: in this embodiment, and As and The larger the cavity temperature deviation or core temperature deviation, the more temperature control is needed. The larger the temperature control rate requirement, the more flow rate needs to be adjusted, because flow rate adjustment has a faster rate. Conversely, the smaller the temperature control rate requirement, the more water temperature needs to be adjusted, because water temperature adjustment has a wider adjustment range.

[0036] The preset adjustment threshold is 0.5, which is used as an example for description.

[0037] At the current moment, if the probability of cavity water temperature adjustment is greater than the preset adjustment threshold, the fuzzy control algorithm is used to regulate the coolant temperature in the cavity cooling system. If the probability of cavity water temperature adjustment is less than or equal to the preset adjustment threshold, the fuzzy control algorithm is used to regulate the coolant flow rate in the cavity cooling system to complete the first temperature adjustment of the cavity.

[0038] At the current moment, if the core water temperature adjustment probability is greater than the preset adjustment threshold, the fuzzy control algorithm is used to adjust the coolant temperature in the core cooling system. If the core water temperature adjustment probability is less than or equal to the preset adjustment threshold, the fuzzy control algorithm is used to adjust the coolant flow rate in the core cooling system to complete the first temperature adjustment of the core.

[0039] It should be noted that the fuzzy control algorithm is a well-known technology. Its specific process is as follows: (1) First, fuzzification is performed: the cavity temperature deviation value (core temperature deviation value) is read and quantified into different fuzzy levels through the membership function, where the membership function adopts the Gaussian membership function. (2) Then, regularization is performed: based on expert knowledge, the fuzzy set and the corresponding output action composition are determined. (3) Then, reasoning is performed: the fuzzy input is combined with the rules in the rule base and reasoning calculation is performed. The result of the reasoning is a fuzzy set, where the reasoning calculation process adopts the Sugeno reasoning method. (4) Finally, defuzzification is performed: the fuzzy result is converted into a specific control output, which is specifically achieved by the maximum membership method.

[0040] Step S002: After the first temperature adjustment of the cavity and the core, obtain the temperature value of each monitoring point in the cavity and the core at the next moment after the current moment, as well as the coolant flow rate in the cooling system of the cavity and the core; determine the consistency of the local temperature difference in the temperature zone of the cavity and the core based on the distance between the monitoring points and the temperature value difference between the current moment and the next moment.

[0041] It should be noted that further, it is necessary to determine local temperature difference monitoring points and determine the type of local temperature difference. Based on the temperature deviation between the cavity and core, the above-mentioned temperature adjustment is performed on the cavity and core temperature zones to meet the overall temperature requirements. However, during the mold cooling process of actual injection molded parts, due to factors such as the shape, thickness, and cavity depth of the injection molded parts, different cooling rates occur at different locations on the same injection molded part, resulting in local temperature differences at different locations. In other words, the temperature at a local location in the cavity is different from that at other locations. In this case, local temperature differences exist within the same temperature zone, making it difficult to regulate their temperature. Local temperature differences in the same temperature zone may have different sources. For example, a blockage in the cooling water pipe reduces the water flow, thereby reducing heat exchange and causing local temperature differences. In this case, the local temperature difference cannot be directly adjusted and requires water cooling circuit maintenance. However, the local temperature difference caused by the injection molded part itself can be adjusted through the water cooling system. In this case, to adjust the local temperature difference between the cavity and core, it is first necessary to determine the type of local temperature difference. Before determining the type of local temperature difference, it is first necessary to determine the local temperature difference monitoring point among the abnormal monitoring points in the two temperature zones. Generally, the local temperature difference monitoring point first manifests as a temperature deviation. At the same time, the local temperature difference will cause the temperature deviation of multiple adjacent monitoring points.

[0042] Preferably, in one embodiment of the present invention, the method for obtaining the consistency of the local temperature difference between the temperature zones of the cavity and the core includes: After the first temperature adjustment of the cavity and the core, the temperature value of each monitoring point in the cavity and the core at the next moment after the current moment, as well as the coolant flow rate in the cavity cooling system and the coolant flow rate in the core cooling system are obtained.

[0043] The preset temperature abnormality threshold is 0.7, which is used as an example for description.

[0044] At the next moment after the current moment, obtain the mean of the temperature values ​​of all monitoring points in the cavity, record it as the first mean, and obtain the absolute value of the difference between the temperature value of each monitoring point in the cavity and the first mean The normalized value of is recorded as the abnormal probability of the temperature value of each monitoring point. The monitoring points with abnormal probability of temperature value greater than the preset temperature abnormality threshold are recorded as abnormal monitoring points in the cavity at the next moment of the current moment. The monitoring points with abnormal probability of temperature value less than or equal to the preset temperature abnormality threshold are recorded as normal monitoring points in the cavity at the next moment of the current moment.

[0045] According to the method of obtaining the abnormal monitoring points and normal monitoring points in the cavity at the next moment after the current moment, the abnormal monitoring points and normal monitoring points in the core at the next moment after the current moment are obtained.

[0046] It should be noted that maintaining consistent temperatures across the cavity (core) of an injection mold is crucial to ensuring the quality and dimensional accuracy of the molded part. This consistent temperature prevents uneven plastic flow, inconsistent cooling rates, and differential shrinkage caused by localized overheating or undercooling, all of which can affect the final performance of the molded part. Therefore, the greater the difference between the temperature at each monitoring point and the first mean, the more abnormal the monitoring point.

[0047] The preset quantity threshold N is 3, and this is used as an example for description.

[0048] At the next moment after the current moment, use the Dijkstra algorithm to obtain the shortest path length between any two abnormal monitoring points in the cavity (that is, the length of the shortest path from one abnormal monitoring point along the cavity surface to another abnormal monitoring point), obtain the sum of the shortest path lengths of each abnormal monitoring point in the cavity and all other abnormal monitoring points, record the discreteness of each abnormal monitoring point, and record the top N abnormal monitoring points with the smallest discreteness as the local temperature difference monitoring points in the cavity at the next moment after the current moment.

[0049] It should be noted that the Dijkstra algorithm is a well-known technique, and the specific method is not described here. If the number of abnormal monitoring points in the mold cavity at the next moment after the current moment is less than or equal to 3, the abnormal monitoring point in the mold cavity at the next moment after the current moment is directly recorded as the local temperature difference monitoring point in the mold cavity at the next moment after the current moment.

[0050] According to the method for obtaining the local temperature difference monitoring point in the cavity at the next moment after the current moment, the local temperature difference monitoring point in the core at the next moment after the current moment is obtained.

[0051] It should be noted that the local temperature difference caused by the injection molded part itself is caused by the difference in heat absorption and heat dissipation capabilities of the injection molded part at different positions. At this time, the corresponding local temperature difference is simultaneously manifested in the two temperature zones of the cavity and the core, and the positions where the local temperature difference occurs have a consistent relationship. Therefore, the local temperature difference type can be determined by the correspondence between the positions of the local temperature differences in the two temperature zones and the size of the temperature difference. At the same time, the local temperature difference caused by the injection molded part itself has similar manifestations in the core and cavity. Therefore, the higher the position consistency of the local temperature difference monitoring points in the two temperature zones, the greater the possibility that it is caused by the injection molded part itself. At the same time, the higher the temperature difference consistency of the local temperature difference monitoring points in the two temperature zones, the greater the possibility that it is caused by the injection molded part itself.

[0052] At the next moment after the current moment, from all the local temperature difference monitoring points in the cavity, obtain the local temperature difference monitoring point in the cavity that is closest to each local temperature difference monitoring point in the core, record it as the matching cavity monitoring point, and obtain the distance between each local temperature difference monitoring point in the core and the matching cavity monitoring point. The inverse proportional normalized value of is recorded as position consistency, and the absolute value of the difference between the abnormal probability of the temperature value of each local temperature difference monitoring point in the core and the matching cavity monitoring point is obtained. The inverse proportional normalized value is recorded as the temperature difference consistency, and the average of the position consistency and the temperature difference consistency is recorded as the local temperature difference consistency relationship of each local temperature difference monitoring point in the core. The average of the local temperature difference consistency relationships of all local temperature difference monitoring points in the core is obtained and recorded as the local temperature difference consistency of the temperature zone between the cavity and the core.

[0053] It should be noted that the distance between each local temperature difference monitoring point in the cavity and each local temperature difference monitoring point in the core is obtained based on the Euclidean distance between the monitoring point position coordinates (punching position coordinates). and Respectively and The inversely proportional normalized value of .

[0054] Step S003: Based on the consistency of the local temperature difference in the temperature zones of the cavity and the core, combined with the temperature value difference between the monitoring points in the cavity and the core at the next moment and the coolant flow rate in the cooling system of the cavity and the core, the second temperature adjustment of the cavity and the core is completed respectively.

[0055] Preferably, in one embodiment of the present invention, the method of completing the second temperature adjustment of the cavity and the core separately includes: The preset classification threshold is 0.8, which is used as an example for description.

[0056] At the next moment after the current moment, when the consistency of the local temperature difference between the temperature zones of the cavity and the core is greater than the preset classification threshold, it is determined that the local temperature difference of the injection mold at the next moment after the current moment is caused by the injection molded part itself; when the consistency of the local temperature difference between the temperature zones of the cavity and the core is less than or equal to the preset classification threshold, it is determined that the local temperature difference of the injection mold at the next moment after the current moment is caused by a water pipe failure.

[0057] What needs to be explained is: further, it is necessary to determine the adjustment strategy according to the type of local temperature difference. The above classification of local temperature differences is based on the local temperature difference relationship between the two temperature zones of the core and the cavity, which are the local temperature difference caused by the injection molded part itself and the local temperature difference caused by the cooling water pipe failure. Different treatment methods are required for the two. Among them, local water channels have blockages, scaling, leakage or loose joints, resulting in poor water flow and a sudden drop in heat dissipation efficiency. The root cause of this type of local temperature difference is the physical failure of the water channel, not the thermal balance requirement, so it cannot be directly solved by water flow rate and water temperature regulation. Therefore, the physical failure needs to be solved first, that is, report to the maintenance personnel for pipeline inspection. For the local temperature difference caused by the injection molded part itself, it is necessary to use water temperature regulation and water flow rate regulation to perform secondary temperature regulation based on the actual temperature difference performance. At this point, the local temperature difference and the normal temperature difference exist in the same temperature zone, so direct water temperature adjustment cannot achieve local temperature difference adjustment. This is because water temperature adjustment changes the temperature of the cooling medium itself, thereby changing the heat exchange benchmark of the entire temperature zone cooling circuit. At this time, water temperature adjustment based on the local temperature difference will cause the temperature of other normal areas in the entire circuit to change, causing the temperature of the normal area to not meet the actual temperature requirements. Adjusting the water flow rate, on the other hand, changes the heat exchange efficiency and does not change the heat exchange benchmark, so the impact on the normal area is relatively small. Therefore, for the local temperature difference caused by the injection molded part itself, water flow rate adjustment is prioritized. The adjustment of water flow rate is mainly based on the magnitude of the local temperature difference. Generally, the larger the local temperature difference, the greater the water flow rate adjustment. However, as the water flow rate increases, the efficiency of water flow rate adjustment for mold temperature decreases. There is also a limited flow rate for water flow rate adjustment of mold temperature. The closer the water flow rate is to the limited flow rate, the lower the adjustment efficiency.

[0058] The preset constant is 1, and the preset limited flow rate is 3 meters per second, that is, the limited flow rate of water flow rate for adjusting the mold temperature. This example is used for description.

[0059] At the next moment after the current moment, when the consistency of the local temperature difference between the temperature zones of the cavity and the core is greater than the preset classification threshold, obtain the mean of the temperature values ​​of all abnormal monitoring points in the cavity (core), record it as the second mean, obtain the mean of the temperature values ​​of all normal monitoring points in the cavity (core), record it as the third mean, and record the absolute value of the difference between the second mean and the third mean as the size of the local temperature difference of the cavity (core). Based on the principle of fuzzy control, determine the initial adjustment amount of the water flow rate according to the size of the local temperature difference of the cavity (core). Obtain the difference between the preset restricted flow rate and the coolant flow rate in the cavity (core) cooling system , when the difference When it is greater than 0, the difference The inverse proportional normalized value is recorded as the degree to which the current water flow rate is close to the restricted flow rate. If the value is less than or equal to 0, the preset constant is recorded as the degree to which the current water flow rate approaches the restricted flow rate. The product of the current water flow rate's proximity to the restricted flow rate and the initial water flow rate adjustment is taken as the water flow rate adjustment correction. The sum of the water flow rate adjustment correction and the initial water flow rate adjustment is recorded as the final water flow rate adjustment. Based on the final water flow rate adjustment, the coolant flow rate in the cavity (core) cooling system is regulated at the next moment after the current moment, completing the second temperature adjustment of the cavity (core).

[0060] What needs to be explained is: express The inversely proportional normalized value of .

[0061] At the next moment after the current moment, when the consistency of the local temperature difference between the temperature zones of the cavity and the core is greater than the preset classification threshold, the second temperature adjustment of the core is completed in the same manner as the second temperature adjustment of the cavity.

[0062] Based on the above operations, the secondary temperature adjustment in the mold temperature control is determined, that is, the mold temperature control is achieved by adjusting the water flow rate of the cooling circuit.

[0063] So far, the present invention is completed.

[0064] In summary, in an embodiment of the present invention, the first temperature adjustment of the cavity and the core is completed based on the difference between the temperature value of the cavity and the core at the current moment and the required temperature value. After the first temperature adjustment of the cavity and the core, the temperature value of each monitoring point in the cavity and the core at the next moment after the current moment, as well as the coolant flow rate in the cavity and core cooling system, are obtained, thereby determining the consistency of the local temperature difference in the temperature zone of the cavity and the core, and completing the second temperature adjustment of the cavity and the core respectively. The present invention can improve the accuracy of injection mold temperature control, which is conducive to the high-precision production of high-precision automotive parts.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for controlling the temperature of an injection mold for the production of automotive parts, characterized in that: The method comprises the following steps: Obtain the current temperature values ​​of the cavity and core and the required temperature values; determine the probability of water temperature adjustment of the cavity and core based on the difference between the current temperature values ​​of the cavity and core and the required temperature values; and perform the first temperature adjustment of the cavity and core based on the probability of water temperature adjustment of the cavity and core; After the first temperature adjustment of the cavity and the core, the temperature value of each monitoring point in the cavity and the core at the next moment after the current moment, as well as the coolant flow rate in the cooling system of the cavity and the core, are obtained; based on the distance between the monitoring points and the temperature value difference between the cavity and the core at the next moment after the current moment, the consistency of the local temperature difference in the temperature zone of the cavity and the core is determined; According to the consistency of the local temperature difference in the temperature zones of the cavity and the core, combined with the temperature value difference between the monitoring points in the cavity and the core at the next moment and the coolant flow rate in the cooling system of the cavity and the core, the second temperature adjustment of the cavity and the core is completed respectively.

2. The method for controlling the temperature of an injection mold for producing automobile parts according to claim 1, wherein: The specific steps of determining the probability of adjusting the water temperature of the cavity and the core are as follows: At the current moment, obtain the absolute value of the difference between the required temperature values ​​of the cavity and the core, and record it as the theoretical temperature difference value between the cavity and the core; obtain the absolute value of the difference between the temperature values ​​of the cavity and the core, and record it as the actual temperature difference between the cavity and the core; determine the required temperature adjustment rate according to the actual temperature difference between the cavity and the core and the theoretical temperature difference between the cavity and the core; obtain the absolute value of the difference between the required temperature value of the cavity and the temperature value, and record it as the cavity temperature deviation value; obtain the absolute value of the difference between the required temperature value of the core and the temperature value, and record it as the core temperature deviation value; determine the probability of water temperature adjustment of the cavity and the core according to the required temperature adjustment rate, the cavity temperature deviation value and the core temperature deviation value.

3. The method for controlling the temperature of an injection mold for producing automobile parts according to claim 2, wherein: The specific steps of determining the temperature adjustment rate requirement value are as follows: A normalized value of the absolute value of the difference between the actual temperature difference between the cavity and the core and the theoretical temperature difference between the cavity and the core is obtained, and recorded as the temperature adjustment rate requirement value.

4. The method for controlling the temperature of an injection mold for producing automobile parts according to claim 2, wherein: The method of determining the probability of water temperature adjustment of the cavity and the core, respectively, according to the temperature adjustment rate requirement value, the cavity temperature deviation value, and the core temperature deviation value, comprises the following specific steps: Obtain the normalized value of the product of the inverse proportional value of the temperature regulation rate requirement value and the cavity temperature deviation value, and record it as the cavity water temperature regulation probability; obtain the normalized value of the product of the inverse proportional value of the temperature regulation rate requirement value and the core temperature deviation value, and record it as the core water temperature regulation probability.

5. The method for controlling the temperature of an injection mold for producing automobile parts according to claim 1, wherein: The first temperature adjustment of the cavity and the core is completed according to the probability of the water temperature adjustment of the cavity and the core, and the specific steps include the following: At the current moment, if the cavity water temperature adjustment probability is greater than the preset adjustment threshold, the fuzzy control algorithm is used to adjust the coolant temperature in the cavity cooling system. If the cavity water temperature adjustment probability is less than or equal to the preset adjustment threshold, the fuzzy control algorithm is used to adjust the coolant flow rate in the cavity cooling system to complete the first temperature adjustment of the cavity. According to the method of completing the first temperature adjustment of the cavity, the first temperature adjustment of the core is completed according to the probability of the core water temperature adjustment.

6. The method for controlling the temperature of an injection mold for producing automobile parts according to claim 1, wherein: The specific steps of determining the consistency of the local temperature difference between the temperature zones of the cavity and the core are as follows: At the next moment after the current moment, the mean of the temperature values ​​of all monitoring points in the mold cavity is obtained, recorded as the first mean value, and the normalized value of the absolute value of the difference between the temperature value of each monitoring point in the mold cavity and the first mean value is obtained, recorded as the abnormal probability of the temperature value of each monitoring point, and the monitoring points with abnormal temperature values ​​greater than the preset temperature abnormality threshold are all recorded as abnormal monitoring points; According to the distribution of abnormal monitoring points in the mold cavity at the next moment after the current moment, a local temperature difference monitoring point in the mold cavity at the next moment after the current moment is selected from the abnormal monitoring points; According to the method for obtaining the local temperature difference monitoring point in the cavity at the next moment after the current moment, the local temperature difference monitoring point in the core at the next moment after the current moment is obtained; The consistency of the local temperature difference between the cavity and the core is determined based on the distance between the local temperature difference monitoring points and the probability of abnormal temperature values ​​between the current moment and the next moment.

7. The method for controlling the temperature of an injection mold for the production of automobile parts according to claim 6, wherein: The specific steps of selecting the local temperature difference monitoring point in the cavity at the next moment from the current moment from the abnormal monitoring points are as follows: A preset quantity threshold N is set. At the next moment after the current moment, the Dijkstra algorithm is used to obtain the shortest path length between any two abnormal monitoring points in the cavity. The sum of the shortest path lengths of each abnormal monitoring point in the cavity and all other abnormal monitoring points is obtained, which is recorded as the discreteness of each abnormal monitoring point. The top N abnormal monitoring points with the smallest discreteness are all recorded as local temperature difference monitoring points in the cavity at the next moment after the current moment.

8. The method for controlling the temperature of an injection mold for automobile parts production according to claim 6, wherein: The method of determining the consistency of the local temperature difference between the cavity and the core according to the distance between the local temperature difference monitoring points and the temperature abnormality probability between the cavity and the core at the next moment from the current moment includes the following specific steps: At the next moment after the current moment, from all the local temperature difference monitoring points in the cavity, obtain the local temperature difference monitoring point in the cavity that is closest to each local temperature difference monitoring point in the core, record it as the matching cavity monitoring point, obtain the inverse proportional normalized value of the distance between each local temperature difference monitoring point in the core and the matching cavity monitoring point, record it as position consistency, obtain the inverse proportional normalized value of the absolute value of the difference in the probability of abnormal temperature values ​​between each local temperature difference monitoring point in the core and the matching cavity monitoring point, record it as temperature difference consistency, record the mean of position consistency and temperature difference consistency as the local temperature difference consistency relationship of each local temperature difference monitoring point in the core, obtain the mean of the local temperature difference consistency relationships of all local temperature difference monitoring points in the core, record it as the local temperature difference consistency of the temperature zones of the cavity and the core.

9. The method for controlling the temperature of an injection mold for automobile parts production according to claim 6, wherein: The second temperature adjustment of the cavity and the core is completed based on the consistency of the local temperature difference between the temperature zones of the cavity and the core, combined with the temperature difference between the monitoring points in the cavity and the core at the next moment and the coolant flow rate in the cooling system of the cavity and the core, and the specific steps include the following: At the next moment after the current moment, for all monitoring points in the cavity, the monitoring points whose temperature abnormality probability is less than or equal to the preset temperature abnormality threshold are recorded as normal monitoring points in the cavity at the next moment after the current moment; When the consistency of the local temperature difference between the temperature zones of the cavity and the core is greater than the preset classification threshold, the mean of the temperature values ​​of all abnormal monitoring points in the cavity is obtained and recorded as the second mean, and the mean of the temperature values ​​of all normal monitoring points in the cavity is obtained and recorded as the third mean. The absolute value of the difference between the second mean and the third mean is recorded as the size of the local temperature difference in the cavity; The second temperature adjustment of the cavity is completed according to the local temperature difference of the cavity and the coolant flow rate in the cavity cooling system; The second temperature adjustment of the core is completed in the same manner as the second temperature adjustment of the cavity.

10. The method for controlling the temperature of an injection mold for producing automobile parts according to claim 9, wherein: The second temperature adjustment of the cavity is completed according to the size of the local temperature difference of the cavity and the coolant flow rate in the cavity cooling system, and the specific steps include the following: Based on the principle of fuzzy control, the initial adjustment amount of water flow rate is determined according to the local temperature difference of the cavity; Gets the difference between the preset restricted flow rate and the coolant flow rate in the cavity cooling system , when the difference When it is greater than 0, the difference The inverse proportional normalized value is recorded as the degree to which the current water flow rate is close to the restricted flow rate. When the difference When it is less than or equal to 0, the preset constant is recorded as the degree to which the current water flow rate is close to the restricted flow rate; Obtain the product of the degree to which the current water flow rate approaches the restricted flow rate and the initial water flow rate adjustment amount, and record it as the correction amount of the water flow rate adjustment amount; The sum of the correction amount of the water flow rate adjustment amount and the initial water flow rate adjustment amount is recorded as the final water flow rate adjustment amount; According to the final water flow rate adjustment amount, the coolant flow rate in the cavity cooling system at the next moment after the current moment is regulated to complete the second temperature adjustment of the cavity.

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